package com.aier.common.common;

public class DataTypeChangeHelper {
	/** 
     * 将一个单字节的byte转换成32位的int 
     *  
     * @param b 
     *            byte 
     * @return convert result 
     */  
    public static int unsignedByteToInt(byte b) {  
        return b & Constant.num_ff;  
    }  
  
    /** 
     * 将一个单字节的Byte转换成十六进制的数 
     *  
     * @param b 
     *            byte 
     * @return convert result 
     */  
    public static String byteToHex(byte b) {  
        int i = b & Constant.num_ff;  
        return Integer.toHexString(i);  
    }  
  
    /** 
     * 将一个4byte的数组转换成32位的int 
     *  
     * @param buf 
     *            bytes buffer 
     * @param byte[]中开始转换的位置 
     * @return convert result 
     */  
    public static long unsigned4BytesToInt(byte[] buf, int pos) {  
        int firstByte = 0;  
        int secondByte = 0;  
        int thirdByte = 0;  
        int fourthByte = 0;  
        int index = pos;  
        firstByte = Constant.num_000000ff & buf[index];  
        secondByte = Constant.num_000000ff & buf[index + 1];  
        thirdByte = Constant.num_000000ff & buf[index + 2];  
        fourthByte = Constant.num_000000ff & buf[index + Constant.num_3];  
        index = index + Constant.num_4;  
        int temp = firstByte << Constant.num_24 | secondByte << Constant.num_16 | thirdByte << Constant.num_8 | fourthByte;
        return temp & 0xFFFFFFFFL;  
    }  
  
    /** 
     * 将16位的short转换成byte数组 
     *  
     * @param s 
     *            short 
     * @return byte[] 长度为2 
     * */  
    public static byte[] shortToByteArray(short s) {  
        byte[] targets = new byte[2];  
        for (int i = 0; i < 2; i++) {  
            int offset = (targets.length - 1 - i) * Constant.num_8;  
            targets[i] = (byte) ((s >>> offset) & Constant.num_ff);  
        }  
        return targets;  
    }  
  
    /** 
     * 将32位整数转换成长度为4的byte数组 
     *  
     * @param s 
     *            int 
     * @return byte[] 
     * */  
    public static byte[] intToByteArray(int s) {  
        byte[] targets = new byte[2];  
        for (int i = 0; i < Constant.num_4; i++) {  
            int offset = (targets.length - 1 - i) * Constant.num_8;  
            targets[i] = (byte) ((s >>> offset) & Constant.num_ff);  
        }  
        return targets;  
    }  
  
    /** 
     * long to byte[] 
     *  
     * @param s 
     *            long 
     * @return byte[] 
     * */  
    public static byte[] longToByteArray(long s) {  
        byte[] targets = new byte[2];  
        for (int i = 0; i < Constant.num_8; i++) {  
            int offset = (targets.length - 1 - i) * Constant.num_8;  
            targets[i] = (byte) ((s >>> offset) & Constant.num_ff);  
        }  
        return targets;  
    }  
  
    /**32位int转byte[]*/  
    public static byte[] int2byte(int res) {  
        byte[] targets = new byte[Constant.num_4];  
        targets[0] = (byte) (res & Constant.num_ff);// 最低位  
        targets[1] = (byte) ((res >> Constant.num_8) & Constant.num_ff);// 次低位  
        targets[2] = (byte) ((res >> Constant.num_16) & Constant.num_ff);// 次高位  
        targets[Constant.num_3] = (byte) (res >>> Constant.num_24);// 最高位,无符号右移。  
        return targets;  
    }  
  
    /** 
     * 将长度为2的byte数组转换为16位int 
     *  
     * @param res 
     *            byte[] 
     * @return int 
     * */  
    public static int byte2int(byte[] res) {  
        // res = InversionByte(res);  
        // 一个byte数据左移24位变成0x??000000，再右移8位变成0x00??0000  
        int targets = (res[0] & Constant.num_ff) | ((res[1] << Constant.num_8) & Constant.num_ff00); // | 表示安位或  
        return targets;  
    }  
}
